Absorber for refrigeration systems



Dec. 4, 1934. KQHLER 1,983,295

ABSORBER F'OR REFRIGERATION SYSTEMS Filed Nov. 11. 1930 etente Dec. 4,1934 D STATES PATENT OFFICE v 1,988,295 ABSORBER FOR REFRIGERATIONSYSTEMS Peter Kohler, Stockholm, Sweden, assi nor, by

mesne poration, New York, Delaware assignments, to Electrolnx Serve]Cor- N. Y.-, a corporation of Application November ll, 1930, Serial No.424,827 In Germany January 24, 1936 lid Claims.

tion will be apparent from the following descriptime taken in connectionwith the accompanying drawing, in which-- Fig. 1 is a diagrtic viewillustrating one application or the invention; and

Fig. 2, a section through the novel absorber of Fig. l.

Belem-ring to the drawing, reference character 10 indicates the boileror generator of an absorption refrigerating apparatus heated by a gasburner B, which refrigerating apparatus, for the purpose ofillustration, may be considered to em-- ploy ammonia as a refrigerant,water as an absorption medium. and hydrogen as a pressure equalizinggas. The boiler 1o is connected with 39 a rectifier ll and a condenser12, evaporator 13,

heat exchanger 14, absorber l5 and a second heat exchanger 16 for thesolution circulated between the boiler and the absorber. The generalmode of operation of an apparatus or this character is well known anddescription of the same is therefore deemed unnecessary.

To the lower portion of the absorber is con-- nected a descending pipe17 which if desired may be cooled by any suitable means as by water orthe like.

To obtain a circulation of the solution in a definite directiondifierences in density must be built up in a system of this character,since for the usual concentration of the strong and weak solutions andthe usual temperatures in the boiler and absorber, only a smalldifference in density is available between the weak hot solution in theboiler and the strong cold solution in the ab= sorber. The levelestablished in the boiler when so heated is only slightly higher thanthat of the absorber. The difierence in density and thereby the drivingforce for the circulation is increased if the pipes between the boilerand absorber are designed to form a U-tube'one leg of which has a erenttemperature than the other. Thus the difierence in weight between colderand warmor strong solution and warmer and colder weak solution is madeeffective in the production of the necessary circulation.

The pipe 17 is bent to form a U-tube having a pair of spaced uprightlegs, one of which connects to the absorber and is adapted to containthe cooler, denser liquid and the other of which connects to the boilerand contains warmer liquid, thus providing liquid columns oi. differentdensities. The leg 18 nearest the boiler extends around the boiler to aremote side and connects to the boiler at 19. The interior of the boileris provided with a partition 20 which serves to force the strongsolution entering the boiler at 19 downthe boiler where it is heatedbefore it can pass out of the boiler at 21 through pipe 22 whichconnects to the absorber. The leg 18 of the pipe 1'? is disposed in heatexchange relation with the pipe 22 and this serves to heat the pipe 18and render the liquid passing up such pipe of less speoific gravity andtherefore assist in the circulating action. A portion of this branchpipe 22 is provided with a wick of gauze 21 or other capillary mediumwhich protrudes into the boiler so that it is moistened directly by theboiler liquid wardly in close proximity to the heated portion of or bythe spray formed as the result of the boling action.

It is of advantage to cool part of the desceng branch 22 in any desiredmanner as with cooling water or the like in pipe 23, as it isadvantageous to remove heat from the weak solution passing to theabsorber so that such weal; solution will enter the absorber with as lowheat content as possible. To cause the heat removal in a descending legof the conduit for weak solution to the absorber aids and acceleratesthe circulation.

"l'he leg of the capillary siphon located in the boiler may have atemperature of 120 to 130 degrees C. The solution in the leg outside theboiler may be lowered to about me degrees C. by the eiiect or coolingthe outer liquid by cooling water, so that a circulating force iscreated which lifts the solution out of the boiler.

In the heat exchanger 16 formed by pipes 17 and 22 the temperature ofstrong solution from the absorber in pipe 17 is raised and thetemperature of weak solution from the boiler in pipe 22 is lowered. Thepipe 22 is also a U-tube having its upright leg nearest the boiler inheat exchange relation with the pipe l? and the upper extremity of itsother upright leg bent over and extending downwardly at 24 to form aninverted U-tube disposed in heat exchange relation with 10&

the pipe 25 connecting the evaporator and absorber through which coldgas passes and by intermediate portion than in the downwardly extendingportion near the absorber. If desired, the capillary active surface orwick 26 which is necessary at both lifting places can also be runthrough the entire length of the pipe. A pipe 28 connects the upperportion of the evaporator with the absorber and permits passagetherethrough of the auxiliary gas.

Since, in apparatus of this kind, the pipes are usually connected to thevessels by welding and the wire wicks might be destroyed during thewelding process, it is advisable, to provide some means of protectingthe wick, to weld a small plate, washer or the like to the pipe beforethe wick is pulled through the pipe and finally the pipe welded inplace. This process eliminates damage to the wick by heat from thewelding. Where the wick does not extend through the entire length of thepipe, it can be inserted after the pipe has been welded in place. It ispreferable to employ this method of the invention also inside theabsorber such as is shown in Fig. 2. In Fig. 2 is shown an absorberwhich consists primarily of a casing 15 which is provided on itsinterior with a longitudinal strip 27 extending throughout the length ofthe same. This strip could be provided with small cavities if desired.The absorber has an inlet opening 28 for the auxiliary gas from theevaporator and an outlet opening 14 for such auxiliary gas. The weakabsorption solution from the boiler is led to the absorber through pipe29 which appropriately contains a capillary wick 30. The enrichedsolution leaves the absorber through pipe 17. The solution coming fromthe boiler is prevented by the strip 2'7 from fiowing directly from thepipe 28 to the pipe 17. The inside of the casing 15 is provided with oneor more layers of wire gauze 31 that suck up the solution by capillarityand erated by the absorption in the absorber is carried off by thecooling water in coil 23 around the absorber casing 15.

The gauze should lie fiat against the interior wall of the casing andmay simply be cut to size and pushed into the tube where its extremitieswill rest against opposite sides of the strip 27, the gauze being heldin place by its own elasticity. If desired it may also .be held in placeby additional means, as by spot welding, soldering with materialindifferent to the operating medium of the apparatus such as tin or thelike.

If further increase in surface of the absorber is desired, anadditional-tube 34 may be inserted and may extend the entire length ofthe absorber and be welded at its extremities to the end plates of thesame. This tube can also be provided with one or more layers of gauze 33and heat liberated is preferably carried of! by a cooling water coil 32of copper or the like secured on the interior of the tube 34. The tube34 is suitably supported on the strip 27 and with additional braces 35circumferentially spaced from such strip so that the tune is held inplace until it is secured at the front and back to the plates ofabsorber. A relatively tight fit should be provided between thelongitudinal strip 27 and the tube 34 and the gauze omitted between thecontacting surfaces to prevent the solution from siphoning directlythrough this gauze to the outlet pipe 17. Ordinarily the engagement ofthe strip 27 and tube 34 is sufilcient to prevent solution from passingtherebetween in any appreciable quantity. However, if desired. the jointmay be made tight by soldering or by grinding the parts together or insome other desired manner.

The invention is not restricted to the showing on the drawing as variouschanges may be made without departing from the spirit and scope of thesame, for example, if the absorber is air cooled, in which case theinner tube is cooled from the outside only with great difiiculty, the

circulating pressure equalizing gas can be led through inner tube 34 tocarry away the heat of absorption liberated there. The inner tube 34 canalso be provided with a slot or opening through which the absorptionliquid may enter and a capillary siphon provided similar to that in theouter tube for transferring the absorption liquid. Also the gas mixturein the inner tube may be caused to flow counter to the flow of theliquid in the outer tube.

The characteristic quality of the capillary siphon may be used in theabsorber as well as in the discharge or supply line, in which instanceit is preferable to bring the capillary siphon of the pipe line indirect capillary connection with capillary active surfaces of theabsorber. It is not only possible to provide the absorber, withcapillary 'active surfaces but other vessels in the system may besimilarly provided.

It is advantageous for an apparatus workingwith small lifting heightsand capillary siphons that the condensate should enter the evaporator insuch a way that a liquid column can be built up in the condensate supplyline. This raises the pressure in the evaporator-absorber systemslightly above the pressure in the boiler condenser system correspondingto this liquid column. This excess pressure in the absorber assists inforcing the strong, solution into the boiler and to overcome thefrictional resistance in the pipe lines, and has very little effect onthe capillary siphon.

-Water precipitated in the rectifier at a higher level than the absorberafter being properly cooled can be returned through a U-tube preferablyconnected to the descending leg 24 of the tube 22 where it will onaccount of its greater density further increase the downward flow.

It will be obvious to those skilled in the art that various otherchanges may be made in the construction and arrangement withoutdeparting invention is not limited to what is shown in the drawing anddescribed in the specification but only as indicated in the appendedclaims.

I claim:

1. An absorber comprising a tube within a tube,

I from the spirit of the invention and therefore the means at the endsof said tubes forming a closed chamber therebetween, inlet and outletconnections for circulation of both liquid and gas through said chamber,and cooling coils secured to the exterior of the outer tube and to theinterior of the inner tube.

2. An absorber comprising a tube within a tube, cooling coils secured tothe exterior of the outer tube and to the interior of the inner tube,and a capillary substance located around the interior of the outer tube.

3. An absorber comprising a tube within a tube, cooling coils secured tothe exterior of the outer tube and to theinterior of the inner tube, anda capillary substance located around the interior of the outer tube andaround the exterior of the inner tube.

4. An absorber comprising a tube within a tube, cooling coils secured tothe exterior of the outer tube and to the interior of the inner tube, acapillary substance located around the interior of the outer tube andaround the exterior of the inner tube, said absorber having spaced inletand outlet connections, and a baflie disposed therebetween wherebyliquid will be transferred by capillarity from the inlet tothe dischargeopening.

5. An absorber comprising a casing having inlet and outlet passages, abaffle disposed longitudinally of the casing, a second casing within thefirst resting on said baflle, and capillary means for transferringliquid from the inlet to the outlet passages on opposite sides of saidbaflie.

6. An absorber comprising substantially horizontal inner and outertubular casings forming a chamber therebetween, means closing the endsof said chamber, a longitudinal partition between said casings in thelower part of said chamber, inlet and outlet connections for liquid tosaid chamber, on opposite sides of said partition, connections for thecirculation of gas through said chamber, a lining of capilliary materialon the walls of said chamber, and means for cooling said casings.

7. An absorber comprising a closed vessel, a baflie extending upwardlyfrom the lower part thereof, means for cooling said vessel, inlet andoutlet connections for liquid on opposite sides of said baflie, a liningof capillary material in said vessel for distributing and transferringliquid over said bafiie in a path of extensive surface, and connectionsfor the circulation of gas through said vessel.

8. An absorber comprising a closed vessel, a partition having a hollowportion and dividing the lower part of' said vessel, inlet and outletconnections for liquid on opposite sides of said over said partition ina path of extensive surface,

connections for circulation of gas through said vessel, and coolingmeans in the hollow portion of said partition.

9. An absorber comprising a closed casing having connections for thecirculation of gas therethrough, a connection for admitting liquid tothe lower part of said casing, capillary means for distributing liquidfrom the lower part over the interior of said casing, and means forcooling said casing.

10. An absorber comprising a closed vessel having connections for thecirculation of gas therethrough, a connection for admitting liquid tothe lower part of said vessel, capillary means for conducting liquidupwardly in said vessel in bodies of extensive surface, and means forcooling said vessel.

11. An absorber comprising a closed vessel having connections forcirculation of gas therethrough, a partition extending upwardly from thelower part of said vessel, an inlet connection for liquid to the lowerpart of said vessel on one side of said partition, a path for liquidformed by wick-like material of extensive surface extending from saidinlet connection over said partition, means for cooling said path, and adischarge conduit for liquid on the other side of the latter.

12. An absorber comprising a closed vessel having connections for thecirculation of gas therethrough, a partition extending upwardly from thelower part of said vessel, means for flowing liquid through said vesselfrom one side of said partition to the other, and a conduit for coolingfluid extending through said vessel in heat exchange relation with saidmeans.

13. An absorber comprising a closed vessel having connections for thecirculation of gas therethrough, inlet and outlet connections for liquidto the lower part of said vessel, an upwardly arched path for liquidbetween said liquid connections formed by capillary material ofextensive surface, and means for cooling said path.

14. An absorber comprising a closed vessel having connections for thecirculation of gas therethrough, inlet and outlet connections for liquidto the lower part of said vessel, a plurality of upwardly arched pathsfor liquid between said liquid connections formed by capillary materialof extensive surface, and means for cooling said paths.

PETER KGHLER.

